Continental ozone issues; monitoring of trace gases, data analysis and modelling of ozone over Europe

Abstract The poster and this paper consist of two parts: (1) Concentrations and internal production of ozone in Europe in relation to different concepts of the critical levels and (2) Exchange of ozone between the atmospheric boundary layer and the free troposphere. The first part describes the evaluation of 1989 ozone data from the EUROTRAC Tropospheric Ozone Research (TOR) project and the Co-operative Programme for Monitoring and Evaluation of Long-range Transmission of Air Pollutants in Europe (EMEP). The data mostly from central and northwestern Europe, show that independent of ways of formulating the critical levels, there are exceedances over large parts of Europe. The second part shows results from a Data Analysis Model that evaluates the transfer of air from the atmospheric boundary layer (ABL) to the free troposphere (FT) and vice versa. This quantity is of importance since it determines the effective emissions of shorter lived species to the global atmosphere. The model was run for the full year of 1989 to study the exchange processes at the location of Uccle (B). For the summer months June, July and August the results releal a net ABL to FT flux of O 3 with a magnitude of 0.43 * 10 −3 mole m −2 day −1 . This number is in agreement with values derived from transport models.